Lock structure



fJuly 12, 1966 SIMON LOCK STRUCTURE Filed April 22, 1963 zwfau), Aw Wwflla United States Patent 3,260,081 LOCK STRUCTURE Harry Simon, 9229 S. Bennett, Chicago, Ill. Filed Apr. 22, 1963, Ser. No. 274,735 1 Claim. (Cl. 70-370) The present invention relates to a lock guard or protection plate which will prevent removal of the lock cylinder by restricting access to it, and particularly will restrict access to that portion of the lock which protrudes outwardly from the door.

There are of course a great variety of kinds and types of locks. One very common type of lock fits into an aperture in a door and has a peripheral flange which is positioned outwardly of the door. This protrusion allows the lock cylinder to be gripped with a tool such as a plyers or a wrench and twisted or pulled from the door. It also allows the insertion of a tool such as a chisel, screwdriver or a puller between the flange or collar and the door so as to pry the lock cylinder loose or to secure a firmer grip on the lock cylinder so as to turn or pull the lock cylinder from the door. While the door, which is normally made of wood or steel, may itself be recessed to receive the forward end of the lock cylinder, such an arrangement would be costly and would require considerable time for its construction. In addition, the edge of the wooden door surrounding the lock would quite easily be broken away to admit access to the end of the lock cylinder. Also, such an arrangement would place the lock cylinder further into the door so that difliculty with thin doors may be encountered. A currently used, but unsatisfactory means to close the space between the cylinder flange and the surface of the door is to provide a collar formed of thin sheet metal around the lock between the door and the flange. Such a collar, even if providing a generally tight fit, is still quite susceptable to being deformed or removed to expose the lock. Further, such a collar offers substantially no protection against the entire protruding portion of the lock cylinder, together with the collar, being gripped and twisted to remove the lock.

Accordingly, it is the prime object of the present invention to provide a highly effective lock guard or protection structure. A more specific object is the provision of a heavy lock cylinder guard plate which restricts access to the portion of the lock cylinder which protrudes outwardly from the door. It is a further object to provide such a lock plate which is constructed in such a manner that it provides, and cooperates with the lock itself to provide, a structure highly resistant to rem-oval or displacement. Still further, an object of the present invention is to provide such a protective structure which is simple and economical to manufacture and install, yet which is rugged and protection-giving.

Various other objects and advantages of the present invention will become obvious from the following description and accompanying drawings, wherein:

FIGURE '1 is an elevational view, with parts broken away, of a lock and guard plate structure which is mounted onto a section of a door, the illustrated structure embodying various features of the present invention;

FIGURE 2 is a fragmentary side view taken generally along line 2-2 of FIG. 1; and

FIGURE 3 is a perspective view of the guard or protection plate.

The illustrated lock structure :10 comprises generally a lock cylinder 12 which is mounted in a door 14 with one end protruding outwardly from the outer surface of the door. This protruding end of the lock cylinder 12 is provided with a peripheral flange 16. A metal guard or protection plate 18 is fixed to the outer surface of the door 14 and surrounds the sides of the protruding end of the lock cylinder 12, including at least the inner part of the flange 16. The guard plate 18 has sulficient thickness to substantially resist distortion or bending. The plate 18, thus, serves to protect the lock cylinder 12, i.e., prevent access to the lock cylinder and particularly to the outwardly protruding end of the lock. The guard plate 18 is bolted to the door I14 and is further held in place 'by the flange 516 of the cylinder 12. Thus, the plate 18 not only prevents-direct access to the lock cylinder 12, but further, it cooperates with the lock cylinder itself to prevent indirect access to the lock by first removing the plate.

Now. to consider the illustrated structure in further detail. The guard plate may obviously be made in various shapes and configurations, and the most desirable bolting means used will depend, at least in part, upon the shape and configuration selected. The description will be limited, however, for convenience, to the preferred embodiment shown in the drawings which is a simple tear drop shape offering various advantages which will be noted in the course of the description.

The door I14, a fragment of which is shown in FIG URE 2, is constructed of wood or the like and has a generally circular aperture 20 extending into it from its outer surface for receiving the lock cylinder 12. Spaced above and apart from the aperture 20 is a small circular hole or opening 22 which extends completely through the door 14. The outer end of the small hole 22 is enlarged to provide a small, circular, retainer block recess 24.

g The illustrated lock !12 is generally cylindrical in shape and has a peripheral flange :16 extending radially therefrom at one end. The edge orrim of the flange 16 is tapered slightly toward the end of the lock cylinder 12. The look cylinder 12 is received within the circular aperture :20 in the door 314, with the flange 16 being disposed outwardly from the outer surface of the door. The inserted portion of the lock cylinder v12 is threaded so as to screw into a housing or a latch mechanism (not shown) which is carried by the door. The lock cylinder 12 may be prevented from rotating, to prevent its removal from the housing and the door, as by means of a set screw (not shown) which engages an axially extending groove 26 in the lock cylinder. The lock cylinder '12 is shown in FIGURE 2 with a key 12a (in phantom) inserted therein preparatory to locking or unlocking the lock.

The illustrated guard or protection plate 18 has a generally teardrop shape. While as noted above, a variety of shapes may be used, the teardrop shape of the preferred embodiment facilitates its effective attachment by a single bolt, as will be described. Such an arrangement of course has the advantage of being simple and economical. The illustrated plate 18 is substantially flat on its inner side so as to fit flush against the outside surface of the door 14, and it has a generally rounded, smooth, outer configuration which is thickest centrally and diminishes toward the edges of the plate. The illustrated plate 18 is made from a sturdy metal such as iron, bronze, or stainless steel. The smooth configuration is preferred as it makes the plate hard to grasp.

The guard plate 18 has a circular hole 28 for receiving the cylindrical lock 12, which hole 28 is located generally centrally of the larger lower portion of the plate. The hole 28 aligns with the aperture 20 f the door when the plate is assembled. The fit between the cylindrical lock 12 and the hole 28 is preferably snug or relatively close, but suflicient room should be allowed to fit the threaded portion of the lock through the hole 28 without damaging the threads. The outer end of the hole 28 is provided with an annular recess 30 which receives the peripheral flange 16 of the lock cylinder 12. The plate 18 protects the flange 16, while the flange 16 in turn aids in holding the plate in position on the door.

On the flat or inner side of the illustrated guard plate 18, and adapted to fit within the recess 24 in the door 14 when the structure is assembled, is a small cylindrical retainer block 32 which has a threaded center hole 34 extending into it. The block 32 is located centrally of the smaller portion of the plate. When the lock structure is assembled, a single retaining bolt or rod 19 passes through the small hole 22 in the door and threads into the threaded hole 34 in the retainer block 32. An enlarged head 38 on the bolt 19 combines with a formed, sheet-metal reinforcing washer 40 to provide a retainer which holds the bolt 19 and thus the plate 18 in place. Of course, more or differently placed bolts may be provided. In particular, if a different configuration. plate 18 is desired, it may be desirable to add further bolts. Suitable additional, blocks and recesses and bolt holes may be provided as needed.

The lock structure is assembled, as shown in FIGURE 2, by passing the lock cylinder 12 through the opening 28 in the guard plate 18 and through the aperture 20 in the door 14. The lock 12 is secured in place in the usual fashion and the plate 18 is also bolted in place. The guard or protection plate 18: fits generally flush against the outer surface ofthe door 14, with the retainer block 32 received within the recess 24. The guard plate 18 is secured in position by passing the retaining bolt 19, through the small hole 22 and screwing it into the retainer block 32.

It is preferable that the peripheral flange 16 of. the lock cylinder 12 rest against the shoulder provided by the annular recess 30, so that the plate 18 is held firmly against the door 14. In addition, the flange 16 cooperates with the wall of the annular recess30 to limit access, by varioustypes of tools, to the part of the lock protruding or extending outwardly from the door. Accordingly, it is preferable that at least a substantial portion of the flange 16 be received within the recess 30. Protecting against the wedging or prying of the lock away from the door is one of. the important features of the guard plate 18, and this feature may be substantially achieved so long as the inner edge of the flange 16 is inserted sufficiently into the annular recess 30 and extends close enough to the sides of that recess to prevent effectively forcing a tool between the flange and the recess wall and/0r under the inner edge or lip of the flange. However, it is also a feature of the structure to prevent the outer end of the lock cylinder 12 from being effectively gripped by a tool and turned or twisted to break or thread it out of its position in the door. Thus, not only is it desirable that the inner lip of the flange 16 be enclosed, but it is also desirable that the flange be sufficiently enclosed so that no substantial or effectively grippable portion is exposed.

Accordingly, to provide the fullest protection, in the preferred embodiment shown in the drawings, the lock cylinder 12 is shown with a relatively close fit between the flange 16 and the recess wall. Further, in the illustrated structure, the outer face of the lock is generally flush with the outer face of the guard plate 18.

In addition to restricting direct access to the lock cylinder 12, the illustrated guard plate 18 is constructed to offer substantial resistance to efforts to remove or displace it so as to ultimately gain access to the lock. The flange 16 and the bolt 19 hold the plate 18 against the door and prevent it from being pryed away. Further, the plate 18 is relatively thick in the lower center area which closely surrounds the lock. Not only is sidewise shifting of the plate 18 thus prevented by engagement of this thicker area with the lock, but in addition, the generally solid block of material comprising the thicker portion of the plate and the lock itself offer considerable resistance to bending of the plate by attempts to pry up its edges, particularly at the lower part of the plate. The retainer block 32 offers protection to the retainer bolt 19 which might otherwise be susceptible to being cut through by a device such as a hacksaw.

Thus, the illustrated structure, which is simple and economical to produce and install, requiring only a single bolt connection, and offering no interference to the action of the locking mechanism, provides substantial protection against forceable entry.

Various changes may be made in the details of the illustrated structure without departing from the spirit and scope of the invention as set forth in the following claim.

What is claimed is:

For use with a mortise lock housing affixed to a door and having an internally threaded opening in alignment with a hole extending from. one surface of the door to the housing, the combination which comprises (A) a lock cylinder including a generally cylindrical body portion adapted to be disposed in the hole of the door,

(1) said body portion having a threaded outer surface proportioned so as to enable one end thereof to be received in threaded engagement within the opening of the lock housing with the other end thereof projecting past the one surface of the door,

(2) said lock cylinder being provided with a flange located at the other end of said cylindrical body portion,

(a) said flange having a diameter somewhat greater than the diameter of said cylindrical body portion and having a given thickness,

(B) and a guard plate having an inner and an outer surface and an upper and a lower edge,

(1) said guard plate being adapted to be secured to the door in encircling relation to the said flange of the said lock cylinder with its inner surface adjacent the one surface of the door and with its upper end uppermost,

(2) said guard plate including a section having a thickness greater than the given thickness of said flange of said lock cylinder,

(21) said guard plate section defining an opening extending therethrough dimensioned so as to enable it to intimately receive the said flange of said lock cylinder,

(1) said opening being located vertically off center so that the distance between the upper edge of said plate and the upper edge of said opening is appreciably greater than the distance between the lower edge of said plate and the lower edge of said opening,

(3) said guard plate including a lip extending into said opening adjacent the inner surface of the plate defining a shoulder intermediate the inner and outer surfaces of said plate adapted to be engaged by the inner surface of said flange of said lock cylinder,

(a) said shoulder being spaced from the outer surface of said plate a distance not sig- 5 6 nificantly less than the given thickness of References Cited by the Examiner said flange so that said flange does not pro- UNITED STATES PATENTS not past the outer surface of said plate a distance sufiicient to enable its side edges 1,479,658 1/1924 Fl'eysmger 70 381 to be grasped within the jaws of a tool, 5 1,579,126 3/1926 a l (4) said guard plate being provided with a re- 1,579,139 3/1926 Phllhps 7O *372 X tainer block projecting from its inner surface ap- 1,814,302 7/1931 Falk 70*379 X proximately midway between the upper edge of 2,550,833 5/1951 Londo 70 134 the plate and the adjacent edge of the said open- FOREIGN PATENTS ing so as to be spaced appreciably from the 10 399,348 10/1933 Great Britain PP edge of sald Plate, 73,417 1/1932 Sweden.

(a) said retainer block being provided with an internally threaded hole adapted to re- PATRICK A. CLIFFORD, Primary Examiner.

ceive an externally threaded bolt extend- ALBE E I ing through the door in the direction of 15 RT xamme" the one surface th f P. TEITELBAUM, Assistant Examiner. 

